Sealing compositions and processes for making same



l' atented Jan. 10, 1950 UNITED STATES PATENT OFFICE- Bernard Gross, San Diego, Calif assignor to Ruhr Aircraft Corporation, Chula Vista, Calif., a corporation of California r No Drawing, Application July 28, 1945, Serial No. 607,675

My invention relates to scaling compositions and processes for making same, and its objects are to produce a sealant which, when applied to cover joints of metallic parts, or openings therethrough or weaknesses therein, is impervious to oil or gasoline and at the same time is resistant to a considerable degree to open fiame; to furnish a sealing composition which may not only be used as a sealant for such coverage, butalso as a gasketing sealant under pressure of rivets or bolts; to bring about good adhesion of such sealant without the use of a special primer when applied directly to metal surfaces; to produce a composition which is rubber-like in character and capable of sustained vibrations without cracking or impairment of structure; to dispense with noxious odors and the use of inflammable material, and in general to furnish a morefefficient flame, oil and gasoline resistant sealant than has heretofore been produced.

At the present time there are many types of sealing compositions on the market for sealing cracks or small openings occurring in or between These compositions are applied metallic parts. in the form of a liquid, a paste, or a putty; and after application either retain their original con sistency, or change into a mass of different charline and even temporarily the eifect of an open My improved sealant has, therefore, been brought into being to meet the need and demand for a sealing composition of these resistant characteristics. Such a sealant, for example, could be used on metal diaphragms behind an airplane 1 engine to seal openings in sheet metal joints or at sheet metal corner relief holes. case of an airplane, through the use of my in vention, the effect of fire upon such seal would ordinarily be avoided. In the absence of an, efiective flame sealant, should a fire break out of the engine of an airplane, and should a blastof air from the propeller thereof blow the flameagainst the metal of its aforesaid diaphragms (then acting as a fire Wall), any melting ofthe" Also in the 6 Claims. (Cl. 260-29. 2)

metal of the diaphragms would tend to start at the'joints or relief holes and quickly spread therefrom. This would be because of the blast effect of the flame upon the edge of the metal at the joints or relief holes if the flame were allowed to pass therethrough. The rapid melting, which occurs after an initial start, results because the flame assisted by the blast of air always acts primarily upon the edge of the metal; However, if my flame resistant sealing compound were used to cover such joints or relief holes, the saidflame would not contact the same and would be permitted to pass over the surface of the metal Without detrimental consequences.

My Sealing composition consists of a mixture of carbon black, zinc chromate, asbestos fibre and polyethylene formal polysulfide in which ingredients are mixed with water, preferably shortly prior to the application of the composition, and are appliedin a paste form to cleaned metal parts without the necessity of a primer. lhese ingredients are mixed with a quantity of water sufficient to form a paste or mortar of such consistency as to enable it to be plastered over the surface of the parts to be sealed. It may be applied in one or more coats or layers in the ordinary manner accordin to the nature of the case and the degree of sealing required. In preparing the said composition I prefer to combine the said ingredients in approximately the following proportions, via:

by weight 8 Zinc chromate, dispersed in water 30 to 40% I by weight 4 Asbestos fibre 17 to 43 Additional water (preferably 80 parts by weight may be added to prevent spoilage if the material is to be stored prior to use).

Preferably the zinc chromate and carbon black dispersion are mixed and kept in a container separate from a receptacle containing a mixture of the polyethylene formal polysulfide dispersion and asbestos; and the two are not combined until just prior to being plastered over the surfaceto be sealed. Soon after application of the coat or layer of my improved sealant, Such sealant so applied assumes a rubber-like consistency. If the sealant is to serve as a gasket between mating metal surfaces, it is spread in paste form over one of the mating surfaces, and after it acquires a rubber-like consistency with a shore hardness of approximately 50 to 60, it may be bolted or riveted to such mating metallic surface. If such mating surfaces are irregular, the

sealant will cold flow and conform to the space between.thematingmetal surfaces. After this. initial cold flow has' taken place, the pressure. of the bolts will cause the sealant to further cold cure to a shore hardness of between 60 to 70..

After this has taken place, the gasket Will not cold flow further under 11011113131 pressureszproe duced by rivets or bolts for a given conditionon mating surfaces.

My improved sealing compositioneislnowbeing;

weight of (1) 159 parts of a water dispersion of polyethylene formal polysulfide, which is made up by weight of 65 to 75 percent polyethylene formal polysulfide and the balance water; (2) 8 parts of a water dispersion of carbon black which is made up by weight of 40 to 50 percent carbon black and the balance water; (3) 4 parts of a water dispersion of zinc chromate which is made up by weight of to percent zinc chromate and the balance Water; (4) 17 to 43 parts by weight of asbestos fibre; and (5) 80 parts of additionaliwaterr 31 A process for preparing a composition for sealing cracks and openings in metallic structures and applying the same comprising (1) mixing: approximately and by weight (a) 159 partssof water dispersion of polyethylene formal pD -t'sulfide which is made up by weight of 65 to 75l-percenti-polyethylne formal polysulfide and used successfully upon a production basis. thecbalance water; (27) 8 parts of a water dis- Among other recognized advantages, are its excellent sealing properties againsir gasolineeoil and other petroleum products; its provisiomof good adhesion when applied directly toometah surfaces without the necessity of using a primer; 25

its flame resistant qualities hereinbefore referred to; itsrubber-like consistency andiprope erty of adhering. without cracking. to the sun-. faces to whichit is applied."notwithstanding.,the.

vibration. thereof; its ability.- to permit without.

iniury the use ofcleaningfiuids or other solvents its use. as a gasket under. the conditionsabove. set forth; andQits freedom .from. obnoxious .odors and inflammable ingredients.

If desired, particularly where protectioniromt 5,;

open fiameis not desiredflor. required,..the in:

.gredient. of. asbestos fibre could be. dispensed-e with in .the. combinations of ingredients.- above. referred .to, and excellent results. obtained from.

the use .of a sealant made byamixturenf lthe're- 49..

ingpclosely. tothe proportions recited. without re Quiringexact coincidence-therewith 0rsubstan, tial deviationtherefiom.

My invention. may. be embodied. in. other. specific. forms without dpartingfrom. the. spirit.

or essential characteristicsthereon The present; 501

embodiment, as above sets forth, is therefore. to be considered in alllrespectssas. illustrative and; not restrictive, the scope .of my invention beings indicated. by the appended claims rather. than. by

persion of carbon black which is made up by weight of 40' to percent carbon black and the balance water; (0) 4 parts of a water dispersion of zinc-chromate which is made up by weight of 30 to 40 percent zinc chromate and the balance water; and (2) applying the mixture so formed to. the area to be sealed.

4; A processLfori preparing a composition for sealing cracks and openings in metallic structures andapplyingthe same comprising (1) mixingapproximately and byjweight' (a) 159 parts of'a water dispersion of polyethylene formal" polysulfide which. is made up by weight'of to 75, percent polyethylene formal polysulfide. and'the balance water; (1)) 8 partsofa water dispersion of'carbon black which ismade up, by; weightof core 50 percent'carbonblack and the balance water; ((3) 4 parts of a water dispersion" ofzinc chromate which is made up by. weight of 30'to-.40"percentzinc chromate and the balance water; (at) lTto 43 parts of asbestos fibre, .the' mixture forming a paste of such consistency as tolenable' it to .be plastered over the area .to be sealedand"(2)" applying the mixture so formed.

made up; by weiglitof 40; to 50'. percent carbonthe. abovedescription, and 1 all changes. which flkbmckand thebalancewater; and (2) O m ni come within the meaningcandrangesofequivae lency of the claims are therefore intended to be embraced therein.

What I claim and desire to secure by'Letters Patent is: r

1. A'fiame; oil' and gasoline resistant'sealing" composition comprising approximately and by weight'cf (l) lSQ -p'arts of"a'waterdispersionofi' polyethylene formal polysulfide; which-is made the" mixture so formed with approximately a and bygweigh'tISQ'Darts of a water dispersion of polyethylene formal polysulflde which ismade up; by. weight of "65 to YSper'cent ofpolyethyl'ene formal.

w p'olysulflde andthebalance water; and (3) applying the. paste so formed to the area to be sealed.

(ifAipro'c'ess for preparing a composition forsealingprack'sand openings in metallic structures.

u by Weight f 5 15 nt' m 'e as against". the deleterious.actionioiflame, oil. and.

formal polysulfide and the balance wate'r;' (2)- 8 parts'of a water di'spersion ofcarbon black, which is made up byweigh't of 4Gt'o'5'0 percent carbon black. and the balance. water; ,(3)- 4 "parts gasoline andiappl'ying thesame whichcomprises. (I). mixing approximately andby weight (a) 4. parts. of i a water. dispersion .of zinc chromate.

which. is made. upgbyweight .of.30 to.40 percent eta: water dispersionofzinochromate. whichuis. '[dzinc chromate and:thebalance.water-zwith (h) 8.

made-upby Weightof 30-to-40 percent'zinc. chromate and the-balancewaten; (49 17 to'=43 parts.- by weight of asbestosfibrec 21A flame, .oil'tandlgasolinei resistant sealing, composition. comprising. approximately andlby? parts. of. a, water. dispersion of" carbon black which is made-up by'weight of 40 to.50- percent. carbon black. and the. balance. water; (2) mixing. approximately. andtby-s weight (a) '159tparts .-of a-- 75 wateedispersionof.polyethylene formal lpolysule 6 fide which is made up by weight of 65 to 75 percent of polyethylene formal polysulfide and the I UNITED STATES PATENTS balance water with (b) 17 to 43 parts of asbestos u ber Name Date fibre; (3) combining the mixture (1) with the 2,140,672 Gray et a1 D 2 1 7 mixture (2) and (4) applying the paste so formed 3 2,186,284 Denman Jan. 9, 1940 to the areato be sealed. 2,195,380 Patrick Mar. 26, 1940 2,206,643 Patrick July 2, 1940 BERNARD GROSS. 2,219,550 Martin, Jr. Oct. 29, 1940 REFERENCES CITED OTHER REFERENCES The following references are of record in the Barron Modem synthetic Rubbers" Van me of this patent: Nostrand Co. Inc., N. Y., 1944, page 285. 

1. A FLAME, OIL AND GASOLINE RESISTANT SEALING COMPOSITION COMPRISING APPROXIMATELY AND BY WEIGHT OF (1) 159 PARTS OF A WATER DISPERSION OF POLYETHYLENE FORMAL POLYSULFIDE, WHICH IS MADE UP BY WEIGHT OF 65 TO 75 PERCENT POLYETHYLENE FORMAL POLYSULFIDE AND THE BALANCE WATER; (2) 8 PARTS OF A WATER DISPERSION OF CARBON BLACK, WHICH IS MADE UP BY WEIGHT OF 40 TO 50 PERCENT CARBON BLACK AND THE BALANCE WATER; (3) 4 PARTS OF A WATER DISPERSION OF ZINC CHROMATE WHICH IS MADE UP BY WEIGHT OF 30 TO 40 PERCENT ZINC CHROMATE AND THE BALANCE WATER; (4) 17 TO 43 PARTS BY WEIGHT OF ASBESTOS FIBRE. 